US6802346B1 - Process and an arrangement at suction element - Google Patents

Process and an arrangement at suction element Download PDF

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Publication number
US6802346B1
US6802346B1 US10/258,134 US25813403A US6802346B1 US 6802346 B1 US6802346 B1 US 6802346B1 US 25813403 A US25813403 A US 25813403A US 6802346 B1 US6802346 B1 US 6802346B1
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Prior art keywords
level
collecting
vessel
liquid
channel
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US10/258,134
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English (en)
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Paul Olof Meinander
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POM Technology Oy AB
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POM Technology Oy AB
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/66—Pulp catching, de-watering, or recovering; Re-use of pulp-water
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/48—Suction apparatus

Definitions

  • the present invention relates to a process for collecting process water at a paper machine or the like, wherein water from several suction elements provided at the wire is led in such a way that an essentially unbroken liquid column is maintained in the respective outlet pipes of the respective suction elements and said liquid column is made to join common collecting vessels.
  • the invention also relates to an arrangement for collecting process water at a paper machine or the like, said arrangement comprising suction elements provided under the wire section said suction elements being connected by essentially vertical outlet pipes to at least one collecting vessel.
  • the outlet pipes from said elements are generally connected to an essentially open collecting vat, which at the same time often functions as a deaerating means for the air contained in the water.
  • the process water is generally at least partially returned from this collecting vat for joining a suitable phase in the initial part of the process in order to re-use a part of the material and the energy remaining in this water and also in order to reduce the amount of effluents from the process.
  • this so called long system should be able to balance the process both at start-up and during normal operation as well as in case of any operational disturbances, the system normally comprises huge amounts of liquid, which, on the other hand, results in a slow circulation and a process with a tendency to contamination, Since this long system extends over a large portion of the machine, it generally includes many long extensions with inclined or horizontal pipes. Practice has shown that these pipes often create problems since the air which always remains in the water easily forms air pockets which, in turn, results in an instable process with disturbances in pumps and other equipment. The air also causes unwanted foaming which is deposited on free surfaces in tanks and pipes and creates additional disturbances.
  • the system generally includes special deaerating means for removing as much air as possible from the water in order to enable pumping to different parts of the machine.
  • deaerating means for removing as much air as possible from the water in order to enable pumping to different parts of the machine.
  • it is, however, difficult to make these deaerating means sufficiently effective without at the same time creating disturbances in the actual liquid flow. Therefore, a significant amount of unwanted air will in practice always be present in the process water.
  • the object of the present invention is to provide a solution to these problems and to provide an arrangement with a small liquid volume, little contamination risks and a minimal part of free liquid surfaces. At the same time the object is to provide an effective deaeration and a reduction in the drawbacks which are caused by an unwanted foaming.
  • the arrangement should also offer simple and effective means for controlling the process.
  • the process according to the invention is characterized in that the liquid levels of the outlet pipes are regulated by regulating the liquid level in at least one separate level vessel towards which the water from the respective outlet pipes is led in at least one closed and essentially horizontal collecting channel which is common for several outlet pipes in such a way that the liquid in said collecting channel at the same time forms the lower part of said unbroken liquid column.
  • the arrangement according to the invention is characterized in that the collecting vessel is composed of at least one essentially closed and generally horizontal collecting channel to which said outlet pipes connect below the channel liquid level.
  • FIG. 1 discloses a general view of an arrangement according to an embodiment of the invention
  • FIG. 2 discloses an alternative embodiment of the connection between the outlet pipes and the horizontal collecting channel according to the invention
  • FIG. 3 discloses a preferred connection of a barometric pipe from a suction box to the collecting pipe
  • FIG. 4 shows a greatly exaggerated section of a collecting channel such that the bottom of the channel is arranged to be essentially horizontal while its top portion is arranged to be inclined, whereby the height of the channel increases in the direction towards the level vessel, and
  • FIGS. 5 a to 5 c disclose different alternative cross sections of the collecting channel according to the invention.
  • the arrangement according to FIG. 1 generally comprises a paper machine or the like machine wherein a material web 1 running in the direction of the arrow is arranged in a way known per se so that liquid from the web is separately sucked out by suction elements provided in the form of suction boxes 2 , 2 a . . . 2 n or the like elements.
  • a back water tray or save-all tray 3 , 3 a for collecting water which is not sucked out by the suction boxes 2 is arranged under the wire.
  • the save-all tray is generally divided so that a portion 3 , which lies early in the process direction, leads the process water to the so called short system or circulation 4 while a portion 3 a , which lies later in the process direction, leads the process water towards the so called long system 5 .
  • the pumping of these process water portions is performed with degassing pumps 6 , 7 which are described in greater detail e.g. in U.S. Pat. No. 5,861,052.
  • the outlet pipes 8 . . . 8 n of the suction boxes are provided in the form of so called barometric pipes whose upper parts are connected to the suction boxes in a way known per se.
  • the lower parts 16 of the respective outlet pipes 8 . . . 8 n are connected to a common collecting channel 9 via special elements so that the connection 17 lies under the surface 18 of the liquid 19 in the channel 9 , as is more clearly shown e.g. in FIG. 5 a.
  • the collecting channel 9 is disclosed as one single channel, but in practice the channel may also be divided into several separate channels arranged in parallel and/or successively.
  • Parallel channels 9 , 9 m may further be arranged so that each respective channel collects only or mainly liquid of a certain consistency or of a certain origin for further treatment in accordance with the special requirements of that specific liquid fraction.
  • Parallel channels 9 , 9 m may further be used e.g. in case of successive modifications of prior existing plants which have another kind of collecting system, as well as for transporting water e.g. from the suction box 2 m of a top wire, either in combination with water from elsewhere or separately.
  • FIG. 1 such an arrangement is schematically indicated by a partly broken line with the reference numerals 8 m and 9 m , respectively.
  • FIG. 1 shows with level indications 20 , 20 n how the vacuum in the respective suction boxes 2 , 2 a . . . 2 n , 2 is arranged.
  • the vacuum increases in the process direction as the web 1 becomes drier and releases less water.
  • Water and air which is sucked into the suction boxes 2 , 2 a . . . 2 n flows down along the barometric pipes and 8 . . . 8 n and is led into a common liquid stream 19 in the substantially horizontal collecting channel 9 .
  • a certain segregation takes place therein so that the water flows along the bottom of the channel while air and foam 21 accumulate at the top 22 of the channel 9 .
  • the movement in the horizontal collecting channel 9 is primarily maintained with the aid of the pump 7 .
  • a part of the movement is caused by the air enclosed in the water owing to the fact that the collecting channel 9 or especially its top portion 22 as such is arranged to rise slightly in the direction of the pump 9 , which is shown with exaggeration in FIG. 4 .
  • the top portion is further designed as a special channel 22 a for the foam.
  • the collecting channel 9 is connected to a level vessel 10 having a free surface 11 .
  • Said level vessel 10 is used, on one hand, for controlling the actual process by enabling variation of the level of the liquid surface 11 , which is shown by a broken line in FIG. 1 .
  • This general level exists in the shown embodiment also at the free liquid surface 12 at the opposite end of the collecting channel which is suitably connected to the back portion 3 a of the save-all tray.
  • the same level vessel 10 is preferably used also as a foam separator, as disclosed in greater detail below.
  • the foam 21 When water and foam flow in the collecting channel 9 , at least the foam 21 will suitably first encounter an inlet channel 13 to the level vessel 10 . At this inlet the foam 21 and most of the air rises upwards to the surface 11 of the level vessel, from where the foam is removed in a suitable way. The direction of movement in the inlet channel 13 is indicated by an upwards directed arrow. The energy for this movement is suitably provided by the air contained in the water. Having reached the surface 11 , the water is suitably led back to the collecting channel 9 via an outlet channel 14 which is located closer to the inlet of the pump 7 . This results in a continuous liquid movement which is primarily caused by the difference in specific weight between the foaming liquid and the liquid from which the foam 21 has been removed.
  • an embodiment of the invention comprises introducing such water tangentially at the wall of the level vessel 10 , whereby a certain rotation is maintained in the vessel 10 .
  • the collecting channel 9 is preferably construed as a continuous, even, suitably slightly rising, and substantially horizontal channel. There should not be any pockets or other points where foam 21 and dirt may accumulate. At the same time, the total liquid volume in the collecting pipe 9 is much smaller than in conventional arrangements. This provides a large flexibility for instance for quick quality changes. The arrangement also results in a radically reduced sensitivity to disturbances in the whole system.
  • FIGS. 5 a to 5 c the outlet pipes 8 . . . 8 n are connected to the collecting channel 9 in such a way that the orifices 17 of the pipes are all the time below the liquid surface 18 in the channel 9 .
  • FIG. 1 shows generally an especially preferred embodiment wherein the pipes 8 are connected directly to the side of the channel.
  • the pipes 8 . . . 8 n are attached to the channel in such a way that they connect to the bottom of the channel 9 via a bend 16 a .
  • This arrangement actually provides a guarantee against a collapse of the liquid column in the pipe 8 as a result of a too low liquid level in the collecting channel 9 .
  • the bends 16 a must be very carefully designed in order to prevent accumulation of contaminants.
  • the embodiments of FIGS. 1 and 3 are in this respect less sensitive to disturbances since the connection between the pipe 8 and the channel 9 is generally horizontal and preferably even slightly downwards inclined, whereby an accumulation of dirt is effectively prevented.
  • the outlet pipes 8 . . . 8 n , 8 m are suitably construed in such a way that their diameter below the liquid surface of the level vessel 10 is smaller than their volume above said surface, as is shown with rough exaggeration with the reference numeral 8 a in FIG. 1 .
  • FIGS. 5 a to 8 c show that the collecting channel 9 is preferably construed so as to promote an accumulation of foam 21 in its upper part.
  • the channel 9 preferably has a generally oval cross section, which in certain cases may be provided with separate spaces 22 a for foam 21 as is shown in FIG. 5 b .
  • the cross section of the channel is generally rectangular. The height of the channel cross section increases in the direction towards the pump 7 , while the width remains essentially unchanged and the bottom of the channel is suitably horizontal. This results in a channel whose “ceiling” 22 rises in the direction towards the inlet 13 of the level vessel 10 enabling especially the foam 21 to follow this rise.
  • the arrangement may, for instance, be supplemented with suction boxes at a top former arranged above the wire or with other similar devices, from which barometric pipes lead down to the collecting channel 9 or 9 m in a corresponding way.
  • the liquid which is led to the respective channel may be treated either separately alone or in combination with other liquid(s) from some other part of the process.

Landscapes

  • Paper (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
  • Die Bonding (AREA)
  • Sheets, Magazines, And Separation Thereof (AREA)
  • Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
  • Motor Or Generator Cooling System (AREA)
US10/258,134 2000-04-19 2001-04-12 Process and an arrangement at suction element Expired - Lifetime US6802346B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI20000938 2000-04-19
FI20000938A FI107744B (fi) 2000-04-19 2000-04-19 Menetelmä ja järjestely imuelementin yhteydessä
PCT/FI2001/000365 WO2001081676A1 (en) 2000-04-19 2001-04-12 A process and an arrangement at suction element

Publications (1)

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US6802346B1 true US6802346B1 (en) 2004-10-12

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US10/258,134 Expired - Lifetime US6802346B1 (en) 2000-04-19 2001-04-12 Process and an arrangement at suction element

Country Status (8)

Country Link
US (1) US6802346B1 (de)
EP (1) EP1285120B1 (de)
JP (1) JP4982684B2 (de)
AT (1) ATE321168T1 (de)
AU (1) AU2001258427A1 (de)
DE (1) DE60118177T2 (de)
FI (1) FI107744B (de)
WO (1) WO2001081676A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10356576A1 (de) * 2003-12-04 2005-07-07 Voith Paper Patent Gmbh Verfahren zum Führen von an einer Papiermaschine offen anfallendem Siebwasser
FI116575B (sv) * 2004-06-28 2005-12-30 Pom Technology Oy Ab Förfarande och anordning vid pappersmaskin

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865687A (en) * 1972-08-15 1975-02-11 Valmet Oy Viscosity perturbation damper connected with distribution header of papermaking machine headbox
US5567278A (en) 1992-05-19 1996-10-22 Pom Technology Oy Ab Process and apparatus for circulating backwater in a papermaking machine

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865687A (en) * 1972-08-15 1975-02-11 Valmet Oy Viscosity perturbation damper connected with distribution header of papermaking machine headbox
US5567278A (en) 1992-05-19 1996-10-22 Pom Technology Oy Ab Process and apparatus for circulating backwater in a papermaking machine

Also Published As

Publication number Publication date
EP1285120A1 (de) 2003-02-26
JP2003531317A (ja) 2003-10-21
FI107744B (fi) 2001-09-28
ATE321168T1 (de) 2006-04-15
JP4982684B2 (ja) 2012-07-25
DE60118177T2 (de) 2007-03-08
DE60118177D1 (de) 2006-05-11
EP1285120B1 (de) 2006-03-22
FI20000938A0 (fi) 2000-04-19
AU2001258427A1 (en) 2001-11-07
WO2001081676A1 (en) 2001-11-01

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